Of course he sings in Spanish! The movie is IN Spanish! Wikipedia:
Casa de Mi Padre (English: My Father’s House) is an upcoming Spanish-language American comedy film. The film stars Will Ferrell, Gael García Bernal, Diego Luna and Génesis Rodríguez with Matt Piedmont directing a screenplay written by Andrew Steele. The film has been described to be in the style of an “overly dramatic telenovela” and tells the story of Armando Alvarez, who must save his father’s ranch from a powerful drug lord. Casa de Mi Padre is set for release next week.
Here’s the trailer:
Here’s the IMDB page.
We want to see it. Do you?